This invention generally relates to surgical devices, systems, and methods, and more particularly provides structures and techniques for manually aligning a robotic surgery system with a desired surgical site.
In robotically assisted or telerobotic surgery, a surgeon typically operates a master controller to control the motion of surgical instruments at the surgical site. The controller may be separated from the patient by a significant distance (e.g., across the operating room, in a different room, or in a completely different building than the patient). Alternatively, a controller may be positioned quite near the patient in the operating room. Regardless, the controller will typically include one or more hand input devices (such as joysticks, exoskeletal gloves, or the like) which are coupled by a servomechanism to a surgical instrument. More specifically, servo motors articulate the surgical instrument based on the surgeon's manipulation of the hand input devices. During an operation, the surgeon may employ, via the robotic surgery system, a variety of surgical instruments, such as tissue graspers, needle drivers, electrosurgical cautery probes, etc. Each of these structures perform functions for the surgeon, for example, holding or driving a needle, grasping a blood vessel, or dissecting, cauterizing, or coagulating tissue.
A variety of structural arrangements might be used to support the surgical instrument at the surgical site during robotic surgery. It has previously been proposed to support the surgical instrument with a mechanical linkage that is driven by the servomotors so that movement of the hand input devices at the master controller causes the surgical instrument to move in a corresponding manner at the surgical site. The driven linkage or "slave" is often called a robotic surgical manipulator.
Robotic surgery has potential applications for a wide variety of surgical procedures and settings. Patients may benefit from robotic surgery directed by a surgeon who is at a considerable distance from the patient. This may allow treatment of soldiers in a battlefield environment, or treatment of trauma victims at considerable distances from a skilled surgical staff. Of particular importance to the present invention, robotic surgery also may provide significant benefits for performing minimally invasive surgical procedures located near the surgeon, but which are best performed within internal surgical sites which are difficult and/or impossible to access directly using a surgeon's hands.
In traditional minimally invasive surgery, elongate surgical instruments are introduced to an internal surgical site, often through trocar sleeves or cannulas. The surgical site often comprises a body cavity, such as the patient's abdomen. The body cavity may optionally be distended using a clear fluid such as an insufflation gas. Such minimally invasive procedures are often performed under the direction of a surgical imaging system, typically by introducing an endoscope to the surgical site. In traditional minimally invasive surgery, the surgeon then manipulates the tissues using end effectors of the elongate surgical instruments by actuating the instrument's handles while viewing the surgical site on a video monitor.
Robotically assisted minimally invasive surgery instead makes use of a servomechanism to actuate the surgical end effectors of the instruments. This allows the surgeon to operate in a comfortable position without looking one direction (towards the monitor) while manipulating handles of surgical instruments that are oriented in another direction (for example, into the patient's abdomen). As more fully described in U.S. Pat. No. 5,696,837, the full disclosure of which is incorporated herein by reference, a computer processor of the servomechanism can be used to maintain the alignment between hand input devices of the controller with the image of the surgical end effectors displayed on the monitor using coordinate system transformations. This allows the surgeon to operate in a natural position using anthropomorphic hand input devices and motions aligned with the image display, despite the fact that the actual surgical instruments are inserted via otherwise awkward arbitrary access positions.
A variety of linkage arrangements have been proposed for use as a robotic surgical manipulator during minimally invasive robotic surgery. An exemplary linkage arrangement is described in U.S. Pat. No. 5,800,423, the full disclosure of which is incorporated herein by reference. In one embodiment, this linkage makes use of a parallelogram arrangement of members to hold an instrument having a shaft. Such a manipulator structure can constrain movement of the instrument having a shaft so that the instrument pivots about a center of spherical rotation positioned in space along the length of the rigid shaft. By aligning this center of rotation with the access point to the internal surgical site (for example, with the trocar or cannula at the abdominal wall during laparoscopic surgery), an end effector of the surgical instrument can be positioned safely by moving the proximal end of the shaft using the manipulator linkage without imposing dangerous forces against the abdominal wall. Alternative manipulator structures are described, for example, in U.S. Pat. Nos. 5,445,166; 5,855,583; 5,808,665; and 5,184,601; the full disclosures of which are incorporated herein by reference.
While the minimally invasive robotic surgery systems proposed to date appear to offer tremendous advantages for performing a wide variety of procedures, still further improvements would be desirable. In general, it would be desirable to provide improved structures and systems for performing robotic surgery. More specifically, it would be beneficial to enhance the efficiency and ease of use of these systems. For example, it would be beneficial to facilitate the alignment of a surgical manipulator with a desired surgical access point. It would further be desirable to allow the surgeon to begin manipulating tissues immediately upon insertion of the surgical instruments and imaging system, with little or no delay in aligning the hand input devices with the actuation servomechanisms. It would further be desirable to provide robotic surgery systems which could be moved between multiple operating rooms without requiring major structural modifications, complex alignment procedures, or unusual peripheral equipment for the operating room, hospital, or procedure site. It would be best if these improvements allowed normal operating room personnel to rapidly arrange and prepare the robotic surgery system for surgery with little or no specialized training, and with as little impact as possible on the overall cost and complexity of the system.